Then someone will get sued. It is the contractors responsibility and not the contractees responsibility. How many ways do you have to be told this?
“Then someone will get sued.”
I have no idea who told you that you cannot tell people to show you ID before you let them on your property, but that has been explained to you over and over.
Call your local police department and tell them your bizarre thought, and they will lecture you about safety.
As a contractor I know that customers can and should identify who the men that I take on their property are.
ID every single person that comes on your property.